The BBC Panorama TV programme, broadcast on Sunday night, said the then-head of Britain's foreign intelligence agency MI6 had warned Blair and others that the US intelligence on Iraq was being "fixed" around a policy of going to war.
It prompted a sharp response from Donald Andersen, chairman of the British parliament's foreign affairs committee.
He condemned the programme and likened its attitude to that of US film-maker Michael Moore, whose movie "Fahrenheit 9/11" mocked the US case for war.
"The voice was the voice of the BBC, suave and restrained. The sentiments were those of Michael Moore, selective and unbalanced," Anderson told Britain's Press Association.
"The BBC are clearly still smarting from their drubbing over Iraq. For them this revenge was sweet."
The corporation and its reporter Andrew Gilligan were heavily criticised in early 2004 by an official inquiry which looked into a BBC radio report alleging Blair's government exaggerated the case for war in Iraq.
Panorama said that in a meeting chaired by Blair in July 2003, MI6 head Sir Richard Dearlove was on record as saying "the facts and the intelligence" had been "fixed round the policy" by the US President George Bush's administration .
The documentary also said British Foreign Secretary Jack Straw questioned whether former Iraqi president Saddam Hussein posed a sufficient enough threat to justify the invasion of Iraq.
"The voice was the voice of the BBC, suave and restrained. The sentiments were those of Michael Moore, selective and unbalanced. The BBC are clearly still smarting from their drubbing over Iraq. For them this revenge was sweet"
Labour lawmaker Robin Cook, who quit Blair's cabinet in protest over the Iraq war, also told the programme that the prime minister has not been totally honest with the British people.
Blair held back on "the real reason why he believed Britain had to be part of an invasion, which was to prove to the United States' president that we were his most reliable, most sound ally", Cook charged.
"His problem was he could not be honest about that with either the British people or Labour MPs, hence the stress on disarmament."
Brian Jones, who served on the Defence Intelligence Staff from 1987 to 2003, told Panorama that the government had urged MI6 to glean as much information as possible from their limited sources in Iraq to build up a case for war.
"I recollect that there was an appeal, if you like, for people to look and think very closely about the evidence that was available," Jones said.
Most Britons opposed the Iraq
invasion and occupation
The foreign affairs spokesman for the opposition Liberal Democrat party, Menzies Campbell, told Sky News on Sunday that the Iraq war raised issues of trust and credibility likely to affect a general election expected on 5 May.
"Iraq is like a nagging tooth for the prime minister - often quiet but capable of flaring up unexpectedly," he said.
Although debate on Iraq has waned in parliament, it still overshadows Blair personally, dampening the popular appeal that carried him to victory in the 1997 election, then again in 2001.
On the second anniversary of the invasion of Iraq on Saturday, tens of thousands of people marched through London to protest against Britain's military involvement in Iraq.